Questions 26 to 30 are based on the following passage.
　　Even plants can run a fever, especially when they're under attack by insects or
　　disease. But unlike humans, plants can have their temperature taken from 3,000 feet away?straight up. A decade ago, adapting the infrared (红外线) scanning technology developed for military purposes and other satellites, physicist Stephen Paley came up with a quick way to take the temperature of crops to determine which ones are under stress. The goal was to let farmers precisely target pesticide(杀虫剂) spraying rather than rain poison on a whole field, which invariably includes plants that don't have pest(害虫) problems.
　　Even better, Paley's Remote Scanning Services Company could detect crop problems
　　before they became visible to the eye. Mounted on a plane flown at 3,000 feet at night ,an infrared scanner measured the heat emitted by crops. The data were transformed into a color-coded map showing where plants were running "fevers".Farmers could then spot-
　　spray, using 50 to 70 percent less pesticide than they otherwise would.
　　The bad news is that Paley's company closed down in 1984, after only three years. Farmers resisted the new technology and long-term backers were hard to find.But with the renewed concern about pesticides on produce, and refinements in in frared scanning, Paley hopes to get back into operation.Agriculture experts have no doubt the technology works. "This technique can be used on 75 percent of agricultural land in the United States, "says George Oerther of Texas A&M. Ray Jackson, who recently retired from the Department of Agriculture, thinks.remote infrared crop scanning could be adopted by the end of the decade. But only if Paley finds the financial backing which he failed to obtain 10 years ago.
　　26. Plants will emit an increased amount of heat when they are _______
　　A) sprayed with pesticides
　　B) facing an infrared scanner
　　C) in poor physical condition
　　D) exposed to excessive sun rays

　　27. In order to apply pesticide spraying precisely, we can use infrared scanning to
　　_______.
　　A) estimate the damage to the crops
　　B) measure the size of the affected area
　　C) draw a color-coded map
　　D) locate the problem area

　　28. Farmers can save a considerable amount of pesticide by _______.
　　A) resorting to spot-spraying
　　B) consulting infrared scanning experts
　　C) transforming poisoned rain
　　D) detecting crop problems at an early stage

　　29. The application of infrared scanning technology to agriculture met with some
　　difficulties _______.
　　A) the lack of official support
　　B) its high cost
　　C) the lack of financial
　　D) its failure to help increase production

　　30. Infrared scanning technology may be brought back into operation because of _______.
　　A) the desire of farmers to improve the quality of their produce.
　　B) growing concern about the excessive use of pesticides on crops
　　C) the forceful promotion by the Department of Agriculture
　　D) full support from agricultural experts